Punch and die mechanism



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FIP79Q4 June 22, 1943. E. F. sHALLA PUNCH AND DIE MECHANISMS Filed Sept5, 1941 2 Sheets-s L "WM/T0,? 5 ALLA er W Search Rooffi June 22, 1943.sH 2,322,547

I PUNCH AND DIE MECHANISMS Filed Sept. 3, 1941 2 Sheets-Sheet 2 28nvvzwroe E. E SHAL LA ATTOR/Vf) UNITED Search Room STATES PATENT OFFICEr, 2,322,547 PUNCH AND om MECHANISM Edmund F. Shalla, Baltimore, Md.,assignor to Western Electric Company, Incorporated, New York, N. Y., acorporation of New York Application September 3, 1941, Serial No.409,365

4 Claims.

This invention relates to punch and die mechanisms and particularly to ashedder for compound type punch and die mechanisms.

In a compound type punch and die mechanism, the article is usuallyformed complete in one step and after being blanked from the materialand/or perforated is reinserted in the opening in the material andremains therein during the advance of the material and until removed bysuitable means. To return the blanked article to the material there isprovided in one type of compound punch and die mechanism an elasticallymounted shedder reciprocable in the die aperture. During the blankingoperation the shedder yields as the blank moves into the die apertureand during the return movement of the blanking punch the shedder followsand presses the blanked article into the Opening in the material fromwhich it was punched. In the punching of articles such as washers ornuts from some materials, for instance, brass, fine brass dust sliversor particles are produced which have a tendency to work their waybetween the sliding or bearing surfaces of the shedder and cause it tobind or deleteriously score the same. This results in increasedmaintenance on the mechanism and frequent delays in production.

An object of the present invention is to overcome the aboveobjectionable features by providing a simple and practical shedder soconstructed that scoring of its bearing surfaces or binding thereon issubstantially eliminated.

In attaining this object, in one embodiment of the invention as appliedto a compound punch and die mechanism for blanking washers there isprovided a tubular shedder having formed in its outer and innerperipheral surfaces continuous helical grooves. The grooves aresemi-circular in cross-section and the inner grooves are spacedsubstantially closer together than the outer grooves and each groove isopen at its upper end to receive fine dust sliver particles produced inthe blanking operation. In practice any particles tending to get betweenthe inner and outer peripheral surfaces of the shedder and their bearingsurfaces on the perforator and the blanking die aperture, respectively,are lodged in the grooves, thus eliminating deleterious scoring of,

Fig. 2 is a plan view thereof with the punch removed;

Fig. 3 is a fragmentary view similar to Fig. 1 showing the punch andshedder after a blanking operation and before returning to their normalpostions;

Fig, 4 is an enlarged detail vertical sectional View, partly inelevation, of the improved shedder, and

Fig. 5 is a plan view of the shedder.

In the drawings, this invention is illustrated as used in connectionwith a simple form of compound type punch and die mechanism, shownfragmentarily, and indicated in general at IU. By way of illustration,the mechanism 10 is effective to blank washers ll, one at a time, frombrass strip material l2. The mechanism Ill comprises abolster plate 13which is fixedly supported upon a punch press frame I4 and areciprocatory ram (not shown) of the press carries a hollow punch l5,shown fragmentarily.

Fixed to the upper surface of the bolster plate I3 is a die plate holderl6 carrying a die plate l8 having a die aperture l9 which in cooperationwith the reciprocatory punch I5 blanks the washers H from the strip l2.The strip l2 rests upon the upper surface of the die plate l8 and isintermittently advanced after each punching operation by suitablemechanism in a manner well known in the art to present a new surface tothe punch l5. Arranged above and with a suitable clearance from thestrip I2 is an apertured stripper plate 20 supported upon the dial platel8 by a plurality of clamping dogs 2|, the strip in its advance beingguided by the dogs and the stripper plate.

Secured to the die plate holder it within a recess in its bottom surfaceis a plate 24 to which is fixed a perforating punch 25 which extendsupwardly from the plate into an aperture 26 in the die plate holder. Theperforating punch 25 is axially aligned with the die aperture I9 and theblanking punch l5 and a reduced upper end of the punch terminates in theplane of the upper surface of the die plate 18.

A tubular shedder embodying the features of this invention is indicatedat 21 and surrounds the perforating punch 25, and its upper end surfacenormally lies in the plane of the upper surface of the die plate l8. Theshedder 2'! in the operation of the punch and die mechanism I0 slides onthe perforating punch 25 and the peripheral wall of the die aperture l9and is closely fitted thereto. At its lower end the shedder 21 is formedwith a supporting flange 28 which rests upon a yieldable plate 31 whichis fitted closely to the peripheral wall of the die plate-holderaperture 26. The plate 3| through which extends the upper reduced end ofthe perforating punch 25 rests upon a plurality of plunger rods 32arranged to slide in apertures formed in the plate 24, the bolster platel3 and an attached block 34. At their lower ends the plunger rods 32engage the upper surface of a plate 35 which is spaced from a similarplate 36 by a block of rubber 31. The plates 35 and 36 and the block ofrubber 31 are attached as a unit to the block 34 by a screw 38 whichextends therethrough and is threaded in the block 34, the lower end ofthe screw having threaded thereon a pair of nuts 39. By adjusting thenuts 39 on the screw 38 the yieldability of the rubber block 31. may bevaried.

Referring particularly to Figs. 4 and 5, the improved shedder 21 hasformed in its outer and inner peripheral surfaces helical grooves 4| and42, respectively. The grooves 4| and 42 in the present embodiment aresemi-circular in crosssection and each is a continuous groove extendingfrom the upper end of the shedder to the upper surface of the flange 28.As shown, the upper ends of the grooves 4| and 42 are open at the upperend surface of the shedder as indicated at 43 and 44, respectively, fora purpose to be presently described. In order not to deleteriouslyWeaken the wall of the shedder 21 by the forming therein of the grooves4| and 42 the helices of the outer grove 4| are spaced further apartthan the helices of the inner groove 42. In the present. embodiment thespacing is such that the outer helices are aligned with each alternatehelix of the inner groove, thus providing a stronger wall to the shedder21.

It will be apparent that in the operation of the mechanism It] inblanking and perforating washers H from the brass strip material 12 thatfine dust sliver particles are produced during such operation and tendto get between the inner and outer peripheral surfaces of the shedder 21and their bearing surfaces on the perforating punch 25 and theperipheral surface of the blanking die aperture l9 and will readily findlodgement in the grooves 4i and 42, first at their open upper ends 43and 44, respectively, and secondly therebelow along successive helicesof the grooves. Thus the dust particles or slivers are received in thegrooves 4| and 42 and stored therein for subsequent removal andconsequently deleterious scoring of the bearing surfaces of the shedderor the binding thereof is eliminated.

In Fig. 1 the blanking punch I and the shedo'er 21 are in their upperpositions and the punch is about to start a washer blanking operation.During a continuous downward movement of the hollow punch l5 it entersthe apertured stripper plate 2a, engages the strip l2 and blanks thewasher l therefrom and in cooperation with the die aperture l9 and thestationary punch 25 simultaneously perforates it, the washer I| beingcarried below the strip l2 to the position shown in Fig. 3, whichillustrates the mechanism at the end of the blanking and perforatingstroke. The shedder 21 yields during the blanking operation and throughits connection, previously described, with the rubber block 31, theblock is compressed. In the retraction of the punch I5 the rubber block31 expands and moves the shedder 21 upwardly to its normal position(Fig. 1) during which movement the washer H is returned to the openingin the strip l2 from which it was punched. Each successive punchingproduced by the hollow blanking punch I5 and perforating punch 25 risesinto the punch I5 and is removed at its upper end by a blast of airdirected by suitable means (not shown).

It is obvious that the grooves 4| and 42 formed in the shedder 2! do notnecessarily have to be semi-circular in cross section, but may be V-shaped, square or of any other suitable contour. Also, a series ofcircular grooves may be substituted for each of the helical grooves 4|and 42, if desired.

It will be understood that the embodiment herein described is merelyillustrative of the invention and one application thereof, the inventionbeing limited only by the scope of the appended claims.

What is claimed is:

1. In a punch and die mechanism, a die having an aperture, a punch insaid aperture, and a tubular shedder operable in said aperture,surrounding said punch and having an external and internal bearing onthe peripheral surfaces of said die aperture and said punch, saidshedder having external and internal grooves to prevent scoring of itsbearing surfaces, the helices of the external groove being differentlyspaced between helices than the helices of the internal groove.

2. In a punch and die mechanism, a die having an aperture, a punch insaid aperture, and a tubular shedder operable in said aperture,surrounding said punch and having an external and internal bearing onthe peripheral surfaces of said die aperture and said punch, saidshedder having external and internal continuous helical grooves open attheir upper ends in the plane of the upper end surface of the shedderfor receiving dust and sliver particles to prevent scoring of its earingsurfaces, the external groove having a greater spacing between helicesthan the helices of the internal groove.

3. A compound punch and die mechanism for punching articles frommaterial comprising a cooperating reciprocable punch and a stationarydie having an aperture for punching an article from said material duringa downward movement of said punch, and means arranged below the materialfor returning the punched article into the material comprising anelastically mounted shedder member movable in said die aperture duringthe punching operation, said shedder member having an external grooveeffective for receiving dust and sliver particles to prevent scoring thewall of said die aperture.

4. A compound punch and die mechanism for punching articles frommaterial comprising an upper cooperating reciprocable punch and astationary die having an aperture for punching an article from saidmaterial during a downward movement of said punch, a perforating punchbelow the material, and means arranged below and abutting the materialfor returning the punched article into the material comprising a tubularelastically mounted shedder member movable in said die aperture duringthe punching operation and surrounding said perforating punch, saidshedder member having external and internal helical grooves open attheir upper ends in the plane of the upper end surface of the sheddermember for receiving dust and sliver particles to prevent scoring thewall of said die aperture.

EDMUND F. SHALLA.

